Remediation of Lead Contaminated Soils by Stabilization/Solidification

Most available remediation technologies for treatment of heavymetal contaminated soils are very expensive and result in residues requiring further treatment. Stabilization/solidification (immobilization) techniques however, which aredesigned to decrease leaching potential of heavy metals from soil by addition of chemical additives, provide very cost-effective solutions for heavy metal contaminated soils. Thisstudy investigates the most efficient additive for immobilization of lead. To achieve this goal, several leachingexperiments were conducted for mixtures of different additives(lime, activated carbon, clay, zeolite, sand and cement) withartificially Pb contaminated (spiked) soil samples in accordancewith the Toxicity Characterization Leaching Procedure (TCLP) developed by U.S. EPA. Results showed that among the additivestried, activated carbon, clay, zeolite and sand are not very efficient for Pb immobilization. On the other hand, lime andcement are significantly effective in Pb immobilization with 88% efficiency at 1:21 lime:soil ratio and 99% efficiency at1:15 cement:soil ratio, respectively.     

Inter and intra-species Inter Simple Sequence Repeat (ISSR) variations in the genus Cicer

Intra and inter-species ISSR variation and use of ISSR markers in determination of genetic relationship were investigated in an accession collection representing twoperennial and six annual Cicerspecies. Screening of Ciceraccessions with SSR primers revealed highly reproducible amplicon profiles with relatively high multiplex ratios. Many of the primers generated amplicon profiles with which not only the differences among species can readily be identified, but also polymorphisms within species could be detected more efficiently. PCR products at 150 gel positions detected using six SSR primers in Cicer accessions were treated as dominant DNA markers and utilized to compute the distances among accessions and species. Cluster analysis of accessions and species revealed groupings that corroborate our previous studies of relationships based on allozyme and AFLP analysis. Consistent with the AFLP analysis carried out in the same accession collection, ISSR-based groupings indicated that perennial C. incisumis genetically close to the annuals of the second crossability group (C. pinnatifidum,C. bijugum, C. judaicum) while C. reticulatum is the closest wild species to the cultivated chickpea. ISSR-based variation estimates were relatively higher when compared to previous estimates computed from RAPD and AFLP data. Technically, ISSR analysis combines the PCR-based targeting of microsatellite-associated polymorphisms with no prior sequence requirement and stringent PCR conditions. Similarly, when compared to AFLP analysis, it is less technically demanding allowing to survey polymorphic loci in the genome. Thus, ISSR-PCR technology is a reliable, fast, and cost-effective marker system that can be used to study genetic variation and genetic relationships in the genusCicer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Seed treatments to overcome salt and drought stress during germination in sunflower (Helianthus annuus L.)

The treated seeds (control, KNO₃ and hydropriming) of sunflower (Helianthus annuus L.) cultivar Sanbro were evaluated at germination and seedling growth for tolerance to salt (NaCl) and drought conditions induced by PEG-6000 at the same water potentials of 0.0, −0.3, −0.6, −0.9 and −1.2 MPa. Electrical conductivity (EC) values of the NaCl solutions were 0.0, 6.5, 12.7, 18.4 and 23.5 dS m⁻¹, respectively. The objective of the study was to determine factors responsible for germination and early seedling growth due to salt toxicity or osmotic effect and to optimize the best priming treatment for these stress conditions.

Results revealed that germination delayed in both solutions, having variable germination with different priming treatments. Germination, root and shoot length were higher but mean germination time and abnormal germination percentage were lower in NaCl than PEG at the same water potential. Seeds were able to germinate at all concentrations of NaCl but no seed germination was observed at −1.2 MPa of PEG treatments. NaCl had less inhibitor effect on seedling growth than the germination. It was concluded that inhibition of germination at the same water potential of NaCl and PEG resulted from osmotic effect rather than salt toxicity. Hydropriming increased germination and seedling growth under salt and drought stresses.     

Teat characteristics in relation to animal temperament during milking in buffaloes,and comparison of buffalo and cow teat morphology

This study aimed to examine the teat characteristics in relation to the animal temperament during milking in the Anatolian buffaloes using ultrasonographic, histomorphological and immunohistochemical methods. The teat canal length (TCL), teat wall thickness (TWT), teat cisternal diameter (TCD), teat diameter (TD), teat length (TL), and teat circumference (TC) values in docile (n = 5) and nervous (n = 7) buffaloes were measured at the 0th, 3rd and 6th minute of stimulation. In additional experiments, comparative histomorphology and immunohistochemical examinations of buffalo (n = 7) and cow teats (n = 8) were performed. It was determined that post-stimulation mean TCL values were significantly higher in nervous buffaloes than those of teats in docile buffaloes (p < .05). A significant positive correlation between TCD and TD, TL and TC in both docile and nervous buffaloes was noted (p < .05). Unlike nervous buffaloes where only 3/14 teat canals were open by 3rd minute of milking stimulation, almost all (9/10) teat canals were observed opened in docile buffaloes. There were fewer muscle but more collagen bundles in buffalo teats compared with cow teats. It seems that temperament of animal during milking effects the milking efficiency, and in nervous buffaloes, probably the stimulation alone may not be sufficient for opening of the teat canal and hence achieve complete milking.     

Screening for resistance of Turkish olive cultivars and clonal rootstocks to Verticillium wilt

Verticillium wilt resistance of 77 olive cultivars including 71 domestic and six foreign ones, and four clonal rootstocks available in the olive gene bank, were tested using a highly virulent isolate (D pathotype) of Verticillium dahliae. The pathogen was stem-inoculated into the own-rooted saplings. Most cultivars and rootstocks were found to be extremely susceptible to the disease. ‘Sinop No. 1’, ‘E?riburun Nizip’, ‘Erkence’, ‘E?riburun Tatayn’, ‘Girit Zeytini’ and ‘Marantelli’ were highly resistant, as their disease severities did not exceed 10%. Additionally, 11 domestic cultivars (‘Sar? Habe?i’, ‘Ya?l?k Çelebi’, ‘Zoncuk’, ‘Dilmit’, ‘?am’, ‘Hurma Karaca’, ‘Erdek Ya?l?k’, ‘Melkabaz?’, ‘Yün Çelebi’, ‘Kan Çelebi’ and ‘Siyah Salamural?k’), two foreign cultivars (‘Arbequina’ and ‘Frantoio’) and one wild clonal rootstock (‘D36’) were found to be resistant, with disease severities less than 30%. On the other hand, the moderately susceptible group comprised ten domestic cultivars (‘Ak Zeytin’, ‘Ya? Çelebi’, ‘Saurani’, ‘Butko’, ‘Gemlik’, ‘Otur’, ‘Ya? Zeytini’, ‘Belluti’, ‘Sinop No. 2’ and ‘Samanl?’), three foreign cultivars (‘Leccino’, ‘Chemlali’ and ‘Ascolana’) and one wild clonal rootstock (‘D9’). The number of cultivars within highly resistant and resistant groups was 17 out of the 71 domestic cultivars from all regions (four from Aegean, seven from southeastern Anatolia, two from Black Sea and three from Marmara).     

Removal of Remazol Red Rb by using Al (III) as Coagulant-Flocculant: Effect of Some Variables on Settling Velocity

This study addresses the research of the removal of a textile dye from aqueous solutions by using aluminum ions as coagulant-flocculant. A simulated textile wastewater was prepared from Remazol Red RB textile dye. The purpose of this study was to investigate the effects of temperature, pH, and concentrations of the cationic surfactant and electrolyte concentration on the settling velocity ofthe simulated textile wastewater. While investigating these factors, levels of variables were determined by considering the characteristicsof traditional textile wastewater like pH, temperature, and dye concentration. Although traditional coagulation-flocculation processesmake use of different aluminium salts as coagulant-flocculent, in this study, Al ions dissolved in pH and temperature of traditional textilewastewater were used. Furthermore, sludge volume index values (SVI) were determined and conductivity measurements carried out. The resultsshowed that, in the working range of these variables, the spectroscopic color measurement revealed 100% decolorization yieldof wastewater. In conclusion, researchers found that the optimum settling velocity conditions were as follows: low temperature (273K),surfactant concentration of 0.10 g L^-1, electrolyte concentration of 0.10 g L^-1, dye concentration of 0.025 g L^-1 and a pH of 10.05. Finally, by conducting experiments twice under the obtained optimum values, mean settling velocity was 0.014 m min^-1 and the mean sludge volume index 140 mL g^-1.     

A new approach for neutron moisture meter calibration: artificial neural network

The neutron moisture meter (NMM) is a widely used device for sensing soil water content (SWC). Calibration accuracy and precision of the NMM are critical to obtain reliable results, and linear regression analysis of SWC against NMM count data is the most common method of calibration. In this study, artificial neural network (ANN) calibration models were developed and compared with linear regression. For this purposes, training and validation data were obtained from 2 calibration and 16 testing plots, respectively. Calibration plots consist of wet and dry soil water conditions separately. Data measured in dry beans and red pepper plots that have four different water levels were used to determine validity of regression and ANN-based calibration models. Volumetric SWC and NMM count ratio measurements were taken for depth intervals of 30 cm throughout a 120-cm-deep soil profile. Several neural network architectures were explored in order to determine the optimal network architecture. Data analyses were conducted for each soil layer and for the whole profile, separately, based on both linear regression and ANN. Linear regression calibration equation coefficients of determination (r ²) for the 0–30, 30–60, 60–90 and 90–120 cm depth ranges calculated by regression models were 0.85, 0.84, 0.72 and 0.82, respectively, and r ² values were 0.94, 0.95, 0.87 and 0.88 based on ANN models, respectively. Using the data set from the entire 120-cm soil profile for calibration by ANN, the r ² value was raised to 0.97.     

Rapid shift from denitrification to nitrification in soil after biogas residue application as indicated by nitrous oxide isotopomers

Nitrous oxide (N₂O) is one of the major greenhouse gases emitted from soils, where it is mainly produced by nitrification and denitrification. It is well known that rates of N₂O release from soils are mainly determined by the availability of substrates and oxygen, but N₂O source apportioning, highly needed to advance N₂O mitigation strategies, still remains challenging. In this study, using an automated soil incubation system, the N₂O site preference, i.e. the intramolecular ¹⁵N distribution, was analyzed to evaluate the progression in N₂O source processes following organic soil amendment. Biogas fermentation residue (BGR; originating from food waste fermentation) was applied to repacked grassland soil cores and compared to ammonium sulfate (AS) application, both at rates equivalent to 160 kg NH₄⁺-N ha⁻¹, and to unamended soil (control). The soil cores were incubated in a helium-oxygen atmosphere with 20 kPa O₂ for 43 days at 80% water-filled pore space. 43-day cumulative N₂O emissions were highest with BGR treated soil accounting for about 1.68 kg N₂O-N ha⁻¹ while application of AS caused much lower fluxes of c. 0.23 kg N₂O-N ha⁻¹. Also, after BGR application, carbon dioxide (CO₂) fluxes showed a pronounced initial peak with steep decline until day 21 whereas with ammonium addition they remained at the background level. N₂O dual isotope and isotopomer analysis of gas samples collected from BGR treated soil indicated bacterial denitrification to be the main N₂O generating process during the first three weeks when high CO₂ fluxes signified high carbon availability. In contrast, in the second half after all added labile carbon substrates had been consumed, nitrification, i.e. the generation of N₂O via oxidation of hydroxylamine, gained in importance reaching roughly the same N₂O production rate compared to bacterial denitrification as indicated by N₂O SP. Overall in this study, bacterial denitrification seemed to be the main N₂O forming process after application of biogas residues and fluxes were mainly driven by available organic carbon.